Northern Ireland firm The Yellow Door has said it will create 35 new jobs after winning a deal worth up to £6m to provide catering at Hillsborough Castle.
The Co Down castle will open to the public on April 10 following a £20m investment by Historic Royal Palaces.
Yellow Door founder Simon Dougan and his partner Barry Smyth won the five-year contract to provide catering at the new Castle Cafe and Stable Yard Tea Room.
Mr Dougan said: "In keeping with the historic nature of Hillsborough Castle we also aim to use varieties of heirloom vegetables such as purple carrots, and some of the more uncommon herbs like lovage and blue hyssop, as well as Chilean guavas, which were reported to be Queen Victoria's favourite fruit."
The Yellow Door will work with the castle's head gardener on its four-acre walled garden.
Gina George, retail director at Historic Royal Palaces, said: "We are pleased to have awarded The Yellow Door the contract for our new catering outlets at Hillsborough Castle and Gardens.
"Following a five-year £20m investment by Historic Royal Palaces, our new cafe and tea room will open to the public when the castle re-opens on April 10."